Enhancement of Physicochemical Properties and Biocompatibility of Shape Memory Polymers by the Addition of Graphene Oxide

Shape memory polymers are intelligent materials that show great application value and potential in many fields. To manufacture biocompatible materials with shape memory properties is an appealing idea and attract many attentions. In our study, we fabricated a composite by adding low content of graphene oxide (GO) in the photo crosslinking four-arm poly(ethylene glycol)-poly(ε-caprolactone) (4A PEG-PCL). Various tests are used to characterize the morphology, physicochemical properties and shape memory effects of the composite. As a result, with a small quantity of graphene oxide, the mechanical properties of the modified material are greatly improved, which is not only attribute to the extremely high strength of graphene but also the interactions of chemical bonds between the graphene oxide and the polymer. Considering the biological applications of the composite, cell experiment is conducted and through the cell proliferation assay, fluorescent staining and morphology observation by the electron microscope. The 4A PCL-PEG/GO showed better cytocompatibility in the adhesion behavior and proliferation rate of clonal murine calvarial preosteoblast cell line (MC3T3-E1). Additionally, expression of ossification genes, runt-related transcription factor (RunX₂), alkaline phosphatase (ALP) and osteocalcin (OCN) are up-regulated, which prove the better osteogenic differentiation ability of 4A PCL-PEG/GO. With these results, it is expected that the GO have great potential in modifying the biosafe shape memory polymers with various excellent performance and broaden its applications in biomedical fields.